The invention relates to a false twist texturing machine for texturing a multiplicity of thermoplastic threads together with a process for producing a textured thread.
A false twist texturing machine of this kind is known from U.S. Pat. No. 5,644,908. In this false twist texturing machine a thread is drawn off from a feeding spool by means of a first delivery device and run in a false twist zone. In the false twist zone are disposed a heating device, a cooling device and a false twist unit. Within the false twist zone a drawing and fixing of the thread takes place. The false twist unit produces a twist which runs in the opposite direction to that of the thread, so that within the cooling device and the heating device, in which a thermal treatment of the thread takes place, the latter exhibits a twist. The thread is after the false twist unit drawn off by a second delivery device and run to a second heating device for the thermal after-treatment. The thread is then run-out of the second heating device by means of a third delivery device and conveyed to a take-up device in which the thread is wound onto a spool. In order to wind on as twist-free a thread as possible, there is provided with the known false twist texturing machine between the third delivery device and the take-up device a vortexing nozzle. In so doing the residual twist contained in the thread is eliminated.
There is known through EP 0 532 458 B1 a false twist texturing machine in which a thread is fed to a false twist zone. In the false twist zone are disposed a first heating device and a false twist unit. The false twist unit produces a twist which runs in the opposite direction to that of the thread. The thread is after the false twist unit run to a second heating device. Downstream of the second heating device is connected a blow nozzle which again imparts a false twist to the yarn, namely in a direction which is opposite to that of the twist produced in the false twist unit.
The problem is encountered with swiftly running threads, however, that the amount of the residual twist increases with the thread speed. In this case the residual twist is imprinted in the thread by the relaxation treatment which has taken place in the second heating device, and it cannot be removed by vortexing.
The present invention is based on the object of developing the false twist texturing machine of the type described above and the process in such a way that the thread is coilable twist-free irrespective of the thread speed.